Pin-type insulator



Patented Jan. 14, 1930 Parana* RICHARD M. KERSCHNER, OF PITTSBURGH, PENNSYLVANIA, ASSTGNOR TO HUEBAED & COMPANY, A CORPORATION OF PENNSYLVANA PIN-TYPE INSULATOR Application :filed August 8, 1927. Serial No. 211,352.

This invention relates to insulators and in particular to pin type insulators.

Pin type insulators are generally composed of glass or porcelain and are of various designs but most of the same have a tapered threaded pin hole adapted to receive a mounting pin. This pin is made of wood, malleable iron or steel and has external threads for cooperating with the threads in the insulator pin hole.

This construction has proven impracticable and undesirable in view of the demand necessitating larger insulators possessing an additional mechanical strength and insulating capacity. The use of the malleable iron pin furnishes Vgreater mechanical strength but at the expense of the insulator, as an insulator mounted on malleable iron threads would shatter or break under a much lower strain than insulators mounted on Wood. food mountings have proven undesirable in view ofthe lack of mechanical strength and many devices have been constructed to make practical the use of malleable iron or steel mounting pins, such as split top insulators or split top insulators With felt insertions and steel pins with forged or cut steed threads have been tried but have never been used to any great extent due to the fact that they were too severe on the insulators.

It is a Well known phenomenon that it is diflicult to make a close fit between insulators and pins in view of the porcelain shrinkage in burning, and that the shrinkage is uneven. It is obvious that the insertion of malleable iron threaded or steel threaded pins into the insulator threads composed of glass or porcelain that do not tit the threads on the insulator pin, will cause the insulator threads to be greatly damaged and often rendered useless.

I have found through practice that a projection of either glass or porcelain will not stand as much strain as a depression and it is one object of this invention to provide an insulator having depressions instead of threads disposed in its pin hole.

It is another object of this invention to provide an insulator mounting comprising an insulator having thread-like depressions disposed in its pin hole and an insulator pin having threads for cooperating with the depressions, the pin threaas being of such design that the strain will be applied to the insulator at the bottom of the depressions instead of at the top.

It is another object of this invention to provide an insulator device comprising an insulator having depressions disposed in its pin hole, an insulator pin for the pin hole and a threaded means for connecting the insulator and pin that shall be self-adjustable.

It is another object of this invention to provide an insulator mounting comprising an insulator having a pin hole therein, the pin hole being provided with thread-like depressions, an insulator pin for the pin hole and a means for connecting the insulator and pin in lined relation, the said means being composed of such material that shall conform to the contour of the depressions disposed in the insulator pin hole.

These and other objects that may bc made apparent throughout the further description are obtained by means of the apparatus hereinafter described and illustrated in the accompanying drawings wherein,

Figure l is an elevational view partly in cross section of an insulator mounting embodying this invention.

Fig. 2 is a view in elevation of an insulator pin embodying' this invention and,

Fig. 3 is a sectional view of Fig. 2.

This invention comprises in general an in- Sulator 11 of the conventional type having thread-like depressions l2 dispose l in the insulator pin hole 13, an insulator pin ls anc a means l5 for connecting the insulator 1 and the insulator in fixed relation.

Referring particularly to Fig. 3 the means 15 is of thimble shape and adapted to be disposed on the upper portion of the pin 11i and fixed thereto by anv suitable means such as shown at 16 and should a more rigid connection be desired in certain applications the internal portion of the thimble may be cemented or otherwise fastened to the surface of the pin 14. The thimble 15 is provided with threads 17 for engaging and cooperating with the depressions 12 in the insulator pin hole 13. The thinible is composed of such material that When the insulator pin holes are small .the top of the thimble threads 17 Will turn over and the side Walls of the threads will bend conforming the outer side of the threads to the inner side of the insulator depressions 12. It is obvious that expansion and contraction strains are also provided for in the same manner. n

The thread 17 of the thimble is twice as deep as the depth of the depressions 1Q disposed in the insulator pin hole 13. The thimble 15 is constructed slightly oversize and overtapere'd With respect to the insulator pin hole 13. rlhis insures a close fit from the bottom of the insulator threads to the Central portion thereof, as the thiinble is slightly7 oversize With respect to the insulator pin hole causing the thirnble thread 17 to conform to the contour of the depressions 12 and causing the strain to be applied to the insulator at the bottom of the depressions 12 instead of at the top.

Accordingly I have provided an insulator mounting comprising an insulator having depressions disposed in its pin hole., an insulator pin and means for connecting the insulator and pin in fixed relation, the sait adapted to apply the strain on the insulator depressions or threads to the bot-ton:l of the depressions or threads` instead of the top as Well as being adapted to self conform to the cooperating depressions or threads for insuring a close lit between the insulator and llVhile l have described and illustrated but one embodiment of this invention it will be apparent topthose skilled in the art that certain changes, modications, substitutions, additions, and omissions may bemade in the apparatus described Without departing` from the spirit and scope of the appended claims.

I claim:

1. Incoinbination with an insulator having a helically grooved pin receiving opening, of an insulator supporting pin provided with threads for engaging the centers onlyv of said grooves With a supporting force.

2. In combination'vvith an insulator having a helically grooved pin receivingopensulator having a helically grooved pin receiving opening,'an insulator pin having a thiinble disposed thereon, the surface of the thiinble being threaded, the'said threads having a greater depth than the groove for engaging the center of the groove With a gripping force, and beveled so that the sides thereof are spaced from the sides of the groove.

5. An insulator device comprising an insulator having a helically grooved pin receiving opening, an insulator pin having a sheet metal thimble disposed thereon, the surface of said thiinble being threaded, the said threads having a greater depth than the groove in said opening for engaging the Vcenter of said groove With a gripping force.

6. An insulator device comprising an insulator having a helically grooved pin receiving opening and an insulator pin having' a threaded surface, the threads thereof bein tapered more sharply than the sides of said groove.

7. An insulator device including an insulator having a helically grooved pin ceiving opening, an insulator supporting pin provided with malleable threads of greater diameter than the diameter of said groove and of greater depth than the depth of said groove.

8. An insulator device including an insulator having a helically grooved pin receiving opening, an insulator supporting pin provided With malleable threads of greater diameter than the diameter of said groove, one end of said threads being of greater dialneter than the other end thereof.

ln testimony whereof, I have hereunto subscribed mv name this 1st day of August, 102.7.

RCHARD M. KERSCHNER. 

